The present invention relates to a padded cap for use on the side or front rails of a waterbed frame.
Although waterbeds have become increasingly popular and sophisticated in their design, most still use a conventionally designed wooden frame to contain the water filled mattress. Campian, U.S. Pat. No. 4,625,351, describes one example of such a frame. A well-recognized problem with the typical waterbed frame is that the wooden rails are uncomfortable for the user while sitting or while entering or exiting the bed. In addition, a standard wooden rail has no means of securing the vertical sections of the waterbed mattress liner which are usually installed between the mattress and the frame box. Consequently, a variety of slip-on padded rail caps have been developed to address these problems. Examples are described by Fisher, U.S. Pat. No. 4,514,871; James, U.S. Pat. No. 4,554,039; Wakeland, U.S. Pat. No. 4,109,887; and Johenning, U.S. Pat. No. 4,197,602.
However, most padded rail caps for waterbeds are sold as accessories to the bed itself, to be installed after the bed is erected and a liner placed. Padded rails previously known and used have been manufactured as one-piece rigid units with a preformed channel which friction-fits over the rail. These designs have several drawbacks. First, they are bulky and therefore expensive to ship and store. Second, their ability to maintain a tight grip on the rail and liner is reduced relatively quickly with use, because of deformation of the channel. Finally, because the tension which produces the friction-fit between the cap channel and exterior of the bed rail runs the full length of the rail, the tension produced at any one point is variable, causing premature wear and possible failure of the top edge of the liner. These problems are further aggravated by the variation in rail thicknesses that are now being sold.
What is needed, then, is a padded rail cap that remains flat and can be folded during shipment and storage and that can retain firm tension when used on rails of varying thickness without causing undue wear of the rail or mattress liner.